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March 29, 2005

QoS , P2P and NBAR

Data classification is one of more important things in QoS but how we can classified data flow through cisco devices (with proper IOS)?and in this days what's important to prioritize?
Data classification depends on each network data flow, for example when you're using voice,video,citrix application and so on , you should plan a strategy for your classification data.

Generally data network is classified to following :
- Voice
- Mission critical (application like citrix)
- Transactional (E-commerce)
- Best-effort (web,email and ...)
- Less-Than-Best-effort (P2P)
*Note : Cisco recommend that your classification doesn't exceeded from 4 or 5 categorize.

These days Peer 2 Peer file sharing applications are a issue for any network which is connected to internet, because it has many data traffic for instance video,mp3 and other larg files so it cause bad situation when the newtrok has congestion.what do you think when you haven't QoS and all of data flow has same priority? yes ofcourse your voice and other low latency data are experienced loss data.
Cisco content networking architecture help you to classified data in later 4-7, it called Network Based Application Recognition (NBAR) so it can regognition some P2P application like Kazza however it depends on PDLM (packet description language module) which is loaded in your cisco device.
You should download the latest PDLM from Cisco web site to up to date application signatures.

In another aspects NBAR can recognize the HTTP GET packets contain the URL through hostname, mime type as well as it has protocol discovery analyzes application traffic pattern in real time and discovery which traffic is running on the network.it uses SNMP to provide that information.

Regarding to this article see the following commands :
ip nbar pdlm pdlm-file
class-map [match-all | match-any] class-name
policy-map policy-name
class class-name
service-policy output
service-policy input
match protocol protocol-name (like kazza)
match protocol fasttrack file-transfer "regular-expression"
ip nbar protocol-discovery
snmp-sever enable traps cndp

Posted by Mehrdad at March 29, 2005 08:48 PM